Electrocatalytic acetylene semihydrogenation (EAH), which uses water as the proton source under ambient conditions, offers an environmentally sustainable and energy‐efficient alternative to conventional thermocatalytic acetylene hydrogenation for purification and synthesis of ethylene (C 2 H 4 ). Recent advances in Cu‐based catalysts and interfacial engineering in three‐phase reactors have enabled EAH to achieve high Faradaic efficiencies (FE > 90%), ampere‐level partial current densities, and stable polymer‐grade ethylene output. This review comprehensively addresses the three pillars: (i) catalyst design for regulating acetylene/ethylene adsorption energetics and suppressing competing reactions; (ii) microenvironment regulation, including interfacial water, local electric fields, and mass transport; and (iii) the influence of reactor engineering on performance. Eventually, we provide an outlook on the current challenges and future research directions for advancing the EAH toward industrial implementation.
Zhou et al. (2026) studied this question.